Wildfires in California have set a new record, but some fire scientists say focusing on that number is doing more harm than good.

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The wildfires here in California have spawned a new word, gigafire. That's a fire that consumes more than 1 million acres, a milestone that the August Complex Fire in Northern California hit this week. Overall, a record-breaking 4 million acres have burned in the state this year. But some fire scientists say focusing only on the numbers of acres burned actually does more harm than good. NPR's Lauren Sommer reports.

LAUREN SOMMER, BYLINE: Early in her career, Crystal Kolden worked as a firefighter. And one summer, she was fighting a blaze in Northern California.

CRYSTAL KOLDEN: You know, every day before our shift, we would drive in a couple of hours in the middle of nowhere and take a stand and try and implement the day's activities against this fire. And it just didn't feel right to me.

SOMMER: They were putting out a wildfire far from any towns in an ecosystem that's adapted to fire. She got more concerned about it when she became a fire scientist at the University of California, Merced.

KOLDEN: If you don't allow fire to burn in those places regularly, you get a buildup of too many trees. And that is what we have seen is driving a lot of these really large fires.

SOMMER: Kolden says that means some fires can be good while others that destroy homes are bad. But she says we don't talk about them like that. Wildfires are often reduced to one metric - how big they are. And big implies bad. Instead, Kolden says the focus should be on the human cost, the number of evacuees or homes threatened.

KOLDEN: Focusing on fatalities, focusing on homes is going to get us to the place where we can say, oh, OK, instead of just trying to suppress the fire, maybe we should be trying to do the things that we know will minimize home losses.

SOMMER: Focusing on the size of fires can obscure another important thing - how dangerous they are.

MATTHEW HURTEAU: The thing that's absolutely striking to me this fire season is how quickly some of these fires are spreading.

SOMMER: Matthew Hurteau is a forest ecologist at the University of New Mexico. He says extreme fires create their own weather.

HURTEAU: A fire can start to create its own winds and then become this basically self-fulfilling prophecy - right? - as it can really start to drive itself forward.

SOMMER: Hurteau says wildfires could be categorized almost like hurricanes are so people know how urgently they need to evacuate because in a warming world, these kinds of fires will only become more common.

Lauren Sommer, NPR News.

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